Cochlear implants may provide a person having sensorineural hearing loss with the ability to perceive sound by stimulating the person's auditory nerve via an array of electrodes implanted in the person's cochlea. An external component of the cochlear implant detects sound waves, which are converted into a series of electrical stimulation signals delivered to the implant recipient's auditory nerve via the array of electrodes. Stimulating the auditory nerve in this manner may enable the cochlear implant recipient's brain to perceive a hearing sensation that is similar to the natural hearing sensation delivered to the auditory nerve.
The effectiveness of the cochlear implant depends not only on the design of the cochlear implant itself but also on how well the cochlear implant is configured for or “fitted” to an implant recipient. The fitting of the cochlear implant, sometimes also referred to as “programming” or “mapping,” creates a set of configuration settings and other data that defines the specific characteristics of the stimulation signals delivered to the implant recipient's auditory nerve. This configuration information is sometimes referred to as the recipient's “program” or “MAP.”
The fitting of the cochlear implant often involves a process that may be called monitoring in which stimulation signals, or simply “stimuli”, are applied via particular electrodes in the cochlear implant and responses to the stimuli are recorded. For each stimulus, a response will be generated by activity within the fibers of the auditory pathway that results from the stimulus. The response may be, for example, an evoked potential from the auditory pathway.
Individually, the responses may be referred to as “electrophysiological signal components.” In order to monitor the responses, several stimuli may be applied and several electrophysiological signal components may be recorded. The electrophysiological signal components may then be combined through one or more of averaging, addition, subtraction, or other methods to produce what may be referred to as an “electrophysiological signal.” Examples of an electrophysiological signal include an electrically-evoked compound action potential (ECAP), an electrically-evoked auditory brainstem response (EBAR), a cortical evoked potential (CEP), and an electrical stapedius reflex (ESR). Other examples are possible as well.
The effectiveness of the cochlear implant additionally depends on continued operation of the cochlear implant during use. For this reason, subsequent monitoring of the cochlear implant may be desirable. To this end, the cochlear implant may be designed to regularly transmit responses to a central database via, for example, a wireless network. The responses may be analyzed in order to evaluate the performance of the cochlear implant.
Thus, monitoring both during fitting and during use of the cochlear implant may aid in improving the effectiveness of the cochlear implant.
Typical systems for monitoring a cochlear implant may include an analyzing device and a recording device. The analyzing device and the recording device are typically connected by one or more physical wires (such as a communication cable), and the recording device is typically communicatively coupled to the cochlear implant by, for example, one or more physical wires or a radio link. The analyzing device may be, for example, a computer. The analyzing device may typically be designed to be capable of intense data mining and computing. The recording device may be, for example, a sound processor, such as one worn behind the recipient's ear. The recording device may typically be designed primarily as a transducer, and may not generally be capable of intense data mining and computing.
During use of the monitoring system, the analyzing device typically identifies a particular electrode or set of electrodes in the cochlear implant through which to provide stimuli in order to receive a desired electrophysiological signal. The analyzing device sends to the recording device an indication of the particular electrode(s), and the recording device transmits to the cochlear implant instructions to apply stimuli via the particular electrode(s). The recording device then records the resulting electrophysiological signal components and passes each of the recorded electrophysiological signal components back to the analyzing device for analysis and processing.
However, one drawback of typical monitoring systems is that large amounts of information must be transmitted between the analyzing device and the recording device. As an example, each electrophysiological signal component must be transmitted from the recording device to the analyzing device. In some cases, this may be as many as 35 signals, and each signal may be 32×1 6 bits. This large volume of information places stringent requirements on both the throughput and the reliability of the link between the analyzing and recording devices. While the physical wires used in typical monitoring systems to connect the recording and analyzing devices may meet these requirements, they also limit the flexibility of the monitoring system. In many applications, it may be desirable to replace the physical wire with a more flexible and convenient wireless link. However, such use of a wireless link is currently not practical because of the stringent throughput and reliability requirements.